A tendon is a band of fibrous tissue that connects the muscle to bone.
Most people with RA have inflammation in the tendons around the joints, especially in the hand.
Nodules may form on the tendons, or the tendon sheath, that surrounds the tendon, may become inflammed.
Why are the tendons affected in RA? Abnormal synovial cells invade and erode, cartilage and bone within the joint. Surrounding muscles, ligaments, and tendons are weakened.
Abnormal immune response causes the body to produce antibodies to its own tissues. The antibodies in rheumatoid arthritis, known as rheumatoid factors, are antibodies against IgG.